The present invention generally relates to magneto-resistance effect magnetic heads employing a magneto-resistance effect film, the resistance of which is changed by the influence of a recorded signal's magnetic field on a magnetic recording medium, the change in the resistance of the magneto-resistance effect film being detected as a playback output voltage. More particularly, the invention relates to a flux guide for efficiently capturing the recorded signal's magnetic flux into the magneto-resistance effect film.
A magneto-resistance effect thin-film magnetic head (MR head) for detecting, as a playback output voltage, the change in resistance of a magneto-resistance effect film (MR film), the resistance value of which is changed by the influence of a recorded signal's magnetic field on a magnetic recording medium, is characterized in that its playback output is not dependent on the running velocity of the medium and in that it exhibits a high playback output despite a slow medium running velocity. Thus the MR head is attracting attention as a magnetic head for realizing a small-size large-capacity hard disc device.
With such an MR head, since the change in resistance of the MR film is produced by changes in the recorded signal's magnetic field on the magnetic recording medium, it is desirable to guide the recorded signal's magnetic flux efficiently to the MR film for improving; the playback signal output. It has, therefore, been contemplated that a flux guide composed of a magnetic thin film can be put in contact with the MR film for efficiently guiding the signal magnetic flux to the MR film.
As such a flux guide, there has been proposed a flux guide formed by a permalloy plating and a laminated film structure composed of Ta and permalloy.
However, it is necessary that the flux guide have high magnetic permeability for efficiently guiding the signal magnetic flux to the MR film and to have magnetically stable characteristics for deriving a stable playback signal output from the MR film. It is also necessary that the flux guide be readily producible while satisfying these conditions of the magnetic characteristics.
Yet, a flux guide formed of permalloy has a low magnetic permeability, on the order of 1500. Moreover, it is magnetically unstable because it has a magnetic wall within the flux guide surface.
On the other hand, a flux guide, made up of laminated film composed of Ta and permalloy, can have a sole magnetic domain, and hence is magnetically stable and may be expected to have high magnetic permeability. However, Ta is a high-melting material and has to be formed into a film by sputtering, so that it is difficult to form into a film by continuous vapor deposition, which is an easy film-forming method.